This invention relates to medical devices and, in particular, to devices, systems, and methods for actuating a plurality of trigger wires for delivery of an endoluminal prosthesis, such as a stent graft delivered in a body lumen.
Deploying an endoluminal prosthesis into a vessel of a patient from a location outside the body is generally known. An endoluminal prosthesis, such as a stent or stent graft, is typically introduced into a vessel in a radially constrained state. Once the endoluminal prosthesis is positioned, it can then be deployed within the vessel by actuation of a trigger wire system.
An endoluminal prosthesis may be either self-expanding or balloon-expandable, or it can have characteristics of both types. A self-expanding endoluminal prosthesis may be delivered to a target site in a compressed configuration and subsequently expanded by removing a delivery sheath, removing trigger wires, and/or releasing diameter reducing ties. With a self-expanding endoluminal prosthesis, the endoluminal prosthesis expands primarily based on its own expansive force without the need for further mechanical expansion. In an endoluminal prosthesis made of a shape-memory alloy such as nitinol, the shape-memory alloy may be employed to cause the endoluminal prosthesis to return to a predetermined configuration upon removal of the sheath or other device maintaining the endoluminal prosthesis in its pre-deployment configuration.
When trigger wires are used as a deployment control mechanism for a stent graft, the trigger wires may releasably couple the proximal and/or distal ends of a stent to a delivery catheter. For example, one or more trigger wires may be used to retain a stent graft at one or both ends to a delivery device. For example, one or more trigger wires may be looped through a portion of a stent or the graft at one or both ends of the prosthesis prosthesis. For example, a stent graft may have proximal and/distal stents having apices. The trigger wires may be disposed through, and pull upon, one or more of the apices to pull the stent closely against the delivery catheter. Alternatively, the trigger wires may run through one or more sutures which are attached to one or more apices of the stent, such as disclosed and shown in U.S. Publication No. 2008/0140178, and in particular FIGS. 3-8 and accompanying text, which disclosure is incorporated by reference in its entirety.
An endoluminal prosthesis is typically introduced into a vessel via a delivery device. Such a delivery device may include a cover or sheath that covers the endoluminal prosthesis. The sheath covering the endoluminal prosthesis is then manipulated within the vessel to a target location for deployment. The sheath is retracted such that it no longer covers the endoluminal prosthesis, allowing the endoluminal prosthesis to expand. The sheath is typically retracted by manually pulling the sheath back in a distal direction. The sheath may also be retracted through the use of at least one trigger wire. The trigger wire may pull on the sheath.
Trigger wires extending from a distal end of the delivery device to the prosthesis may then be retracted by simply pulling on them to release the ends of the prosthesis from the delivery device. The trigger wires can be manipulated from the distal end of the delivery device.